Conventionally, there have been disclosed various methods in which a part of a medium surface, where magnetic ink characters (MICR characters) are printed, is read by using a magnetic head so as to obtain a magnetic regeneration signal for the purpose of character recognition. The magnetic ink characters (MICR characters) are used for checks and the like to be used in financial facilities. Character types thereof typically include E13B and CMC7, and the character types are standardized by ISO 1004 and so on.
At the initial stage in the history of development of the technology for recognizing MICR characters, a major method for character recognition involved reading a magnetic character line by using a magnetic head, inputting a waveform of the magnetic regeneration signal into a logical circuit, and then recognizing the character according to characteristics of a peak position and an output level in the waveform of the magnetic regeneration signal. However, in association with technical advancement of the performance of microprocessors as well as enhancement of memory units in relation with their high-speed operation and large capacity, character recognition by processing a magnetic signal with software has been increasing these years. Furthermore, examples of character recognition include some cases in which not only a magnetic signal but also an image captured by scanning a medium are used together.
In a disclosed method in which a magnetic signal is used, peak intervals in a waveform of a magnetic regeneration signal of a character are determined; and then, according to a combination pattern of the peak intervals, the waveform is correlated with a character having a combination pattern of the peak intervals For example, refer to Patent Document 1 and Patent Document 2, as indicated below:    [Patent Document 1]
Japanese Unexamined Patent Publication (Kokai) No. JP2001-351062    [Patent Document 2]
Japanese Unexamined Patent Publication (Kokai) No. JP2005-157982
However, among checks and so on used practically in the marketplace, some include poorly printed magnetic ink characters even though the characters are still within an allowable range. Therefore, it is required that the technology of character recognition shall recognize those characters within such a border range, being free from any false character recognition.
To describe more in detail, magnetic ink characters being practically used include variations, depending on qualities of magnetic ink, a printing machine, irregularities of medium transfer speed and magnetic properties of a regeneration magnetic head and a magnetizing head. Eventually there arise alterations in the magnetic ink characters; such as a high magnetic force, a low magnetic force, a thick-lined character, a thin-lined character, tilt, and so on.
Furthermore, depending on using condition and storage condition of a check, there may also arise other alterations in the characters, such as having an opening, an unclear character, and a blurring character, etc. so that waveforms of magnetic regeneration signals are deformed in various ways. Particularly, if the check has been stored while being folded, width and intervals of the characters become altered when a folded part is scanned so that accuracy of the magnetic character recognition may be impaired.
Therefore, the methods disclosed by Patent Document 1 and Patent Document 2 described above include procedures through which each interval between peaks in the magnetic waveform is determined so as to convert the interval pattern into ‘1’ or ‘0’ when the interval is wider or narrower than a prescribed interval, respectively. Then, depending on whether or not an array pattern of ‘1’ and ‘0’ agrees with a regular array pattern, presence of an error is detected.
However, those methods are likely to make a misjudgment and probably lead to false recognition when the peak interval in the magnetic waveform is sized around the middle between a wide interval and a narrow interval.
At least an embodiment of the present invention provides a method and an apparatus for magnetic character recognition for recognizing magnetic characters with high accuracy, even when there exists deformation in a pattern of the magnetic waveform.